Nadal now owns 17 Grand Slam championships.
The Spaniard would save just one breakpoint on his way to the business end of the set, where Thiem - serving 5-4 down - reeled off four enforced errors in a row to hand Nadal the set.
After the match, Nadal said that the game needs Thiem and he "will win here in the next few years".
The No. 7-seeded Thiem was trying to become only the second player from Austria to earn a Grand Slam title; Thomas Muster won the 1995 French Open. I was very scared but that's sport - it was very humid. The other three are Rod Laver, Ken Rosewall and Federer, all of whom have won four each.
"He was playing very well, I think, and there is a reason why he won 11 times here", Thiem added.
As he sat down in the French Open lounge on Saturday, Günter Bresnik, Dominic Thiem's coach, was asked about Thiem's upcoming French Open final against Rafael Nadal, the finest clay court tennis player of all time.
57 is the number of titles Nadal holds on the clay court.
Here are the list of numbers behind Rafael Nadal's 11th French Open crown.
He carries that momentum into the next game, going 0-30 up, but the Spaniard comes roaring back.
They call him the "King of Clay". That was part of a five-game run that sent Nadal on his way.
Although Nadal subsequently received treatment on his forearm it seemingly had little adverse effect and, after a second break of serve, his 11th triumph was secured at the fifth time of asking when Thiem sent a return long.
Nadal was up 2-1 at that point.
But he shook off the early nerves and broke back in the third game with forehand victor ― pumping his fists in the direction of coach Gunter Bresnik.
Thiem saved a first breakpoint in that game but couldn't save the second, hitting a forehand wide.
In the women's final Saturday, Romania's Simona Halep defeated American Sloan Stevens in three sets, 3-6, 6-4, 6-1.
The situation got even more perilous after the first set.
But from the moment Nadal broke serve in the 10th game to win the opening set Thiem's belief ebbed away.